UDDER-PYOBACILLOSIS 81 



vate the condition greatly and to favor the primary infec- 

 tion. They may be divided into milk- and stroma- 

 infections. 



Secondary Milk-infection [Secondary Parenchymatous 

 Mastitis~\. — These infections may be strepto- or staphylo- 

 mycosis as well as colibacillosis. The most common, how- 

 ever, is the streptomycosis. They occur one at a time as a 

 rule, but several secondary infections may be present at the 

 same time. 



These secondary infections, especially staphylomycosis, 

 may raise the condition to an acute process and thus induce 

 diffuse necrosis of the quarter and cause the death of the 

 animal. In the earlier stages of pyobacillosis they not 

 infrequently mask the primary condition. 



In developing, pyobacillosis (with secondary milk-in- 

 fection) favors the formation of croupous exudate which 

 begins to form in considerable quantities in the secondary 

 infection. This exudate can remain situated in a teat canal 

 and in this way form a good bridge for the infectious 

 organisms. 



Secondary Stroma-infection. — These secondary stroma- 

 infections may be of two different kinds, acute and 

 chronic. 



Acute secondary stroma-infection occurs only as a 

 secondary infection to wounds. It presumes, consequently, 

 a primary or a secondary wound produced by ulcer- 

 ation. In these wounds secondary infection is the rule. 

 These secondary infections may be strepto- or staphylo- 

 mycosis or colibacillosis. They may occur one at a time 

 or several secondary infections may be present together. 



The single chronic secondary infection which appears to 

 occur is tuberculosis. It is infrequent. Pyobacillosis and 

 its secondar}^ infection, which it somewhat resembles in 

 nature, work together for the destruction of the udder. A 



i-biS 



